Improvement in vacuum-pans



J. -FAIRBURN VAcUUasm-MN. N.177,109. Patented may 9,1876.

N.PETERS, PHOTO-LITHOGRAPHER. WASHINGTON, D C4 vTo all whom it mayconcern:

PATENT OFFICE` .JOHNOFAIRBURR OF UPTON STATION, ASSIGNOR OF ONE-HALF HISRIGHT TO `.ISAAC PLUME, WILSON, OF MONTREAL, CANADA.

IMPROVEMENT IN VACUUM-FANS.

Specification forming part of LetterslPatent No. l 77,109, dated May 9,1876; application filed March 9,1876.

Be it known that l, JOHN lFAIRBURN, of Upton Station, in the county ofBagot, Province of Quebec, in the Dominion of Canada, haveinventedcertain new and useful Improvements in Vacuum-Pans, ot'which I herebydeclare the following specification, when taken in combination with theaccompanying drawing, to be a full, clear, and exact description.

The objects of my improved. vacuum-pan are, first., to overcomeexcessive foaming, which is'so usual in globular vacuum-pans', and whichretards the evaporation of liquids bein g boiled; and, second, toincrease and benetit the circulating of the liquids being evaporated. Asis well known, liquor from barks, while heilig' boiled down for theextract, occasions a great deal ot' trouble and loss by foaming, whichis due, in a great measure, to the imperfect inanner ot' forming thepans in which they are boiled. j

My vacuum-pan, like that ot' ordinary pans, is constructed in threesections, bolted together, as will be seen in the accompanying drawing,in which- Figure l represents a sectional view ot' the p'an embodying myinvention; a'nd Fig. 2 represents a ground plan ot' the heating-surface,showing the relative. position of the drums and steam-coil.

The three separate sections of my pan are indicated by the letters B, E,and F, they beingjoined where the lines a and l) intersect. Thesedifferent sections are bolted together. Thesteam-coil is indicated at O,and, thedrums H having an increasing vertical depth from thecircumference to the center, and which are located in the lower sectionF, the same as in ordinaryy globular vacuum pans, the coils O aresupplied with live steam, which enters at the side ofthe pan, and thesteam, after passing through these coils, exhausts at the bottom. Thesteam-drums H take in live steam at the bottom, and exhaust at the same.The

steam drum or drums are circular boxes inserted with vertical tubes, thetransverse section of which shows a rectilinear gure. It has asuperiority over all other applications for heating-surfaces, for in a-hollow helical band or coil, with or without increasing vertical depth,the liquor is very apt to foam when the live steam `is first let into'the coil, as the liquor'boils in a great rolling body, and Vwill oftenfoam out ot' the pan, when evaporation commences, on account ofthesudden vacuum formed at the lirst condensation of the vapor;

-which cannot be fully appreciated except by one engaged insuperintending a vacuunrpan where so much loss is occasioned by theliquid foaming up and escapinginto the vapor-pipe A.

The most important portion of myimprovement relates to the constructionof the middle l belt or section E, which, instead of being contracted,so as to form perfectly perpendicular sides, similar to an ordinaryvacuum-pan, is made to bulge out at its center, and more contracted atthe topA than vat the bottom. At the top ot' section E I provide aprojecting lip, which is curved inward to prevent` priming, so

that the liquor, instead ot priming up through the pipe A, will bethrown inward. I also contract the top section or dome B to the size ofthe bottom portion oi' the vapor-pipe A, which is secured to it at thispoint. l

It will readily be seen that, as the curves ot' the sections B and E arestruck from a dil'erent radius, and that they are both contracted at thetop, they, together with the bottom or lower section F oi' `the pan,form, as it were, a pau of an ununif'orm ellipse-like shape, which Iclaim to be very favorable to the circulation, and, consequently, rapidevaporation.l

Now, as rapid evaporation is the essentialA virtue ot' a vacuum-pan, andto produce which it is necessary to havea good' circulation, which canonly be effected by having the liquid bash down in the center whenboiling, the most natural way for liquid to boilis upon the sides anddown in the center. Now, by reference to the drawings, it will be seenthat by constructing the pan as I propose to do, the sides, beingcontinuous almost with the bottom, instead ,of rising abruptly, assistin bashing the liquid toward the 'center of the pan, causing it to takethe course indicated by the arrows G. It is believed thaftlthe a1'-rangement and shape of this pan so facilitate A:the heating andcirculation its Huid mn` exhaust-Steam piiie 'K and L enter in the samerelative positions asthose of ordinary vaeunnr pans, so I will not gointo details, as my ilpprovements do notrelate to 'the arrangentien t'of the parte and necessary appendages of the l pan as to its forin- Myimproved pan may also be need for oondeneinn milk, in whioh ease the drnrns willj not reqnire to be so deeniend the vacuum-ran will require tobesomewhatsmelller than that used for making extract. The great objectin oontlensng milk is .to

doit at a low temperature, so as to keep 3a scum or skin from formi-ngenthe surface; hence, it will be found thatfimproved pau will condensemilk far better than any other, Aas `it will evaporate milk tolerablyquick at 100o Fahrenheit. i

Having :thus yfully described my invention, what l claim as nem-anddesire to secure by Letters Patent, is-' A l. A vacuum-pan constructedwith a dome, B, -iniddle ntion Qrbelt E, curving inward from a pointnear its vertical center toward its ends, in combination withthe lowersection F, the whole .founding van in `shape .similar to an ellipsewhose larger axis is vertical.

2. 'lhe inwardly-curved projecting lip, situated on the inside top'edgeofthe middle belt or Section E, to prevent pnimng, substantial I .y asspeeiiedl 3, The circular and vertioallytnbular A:steam (imm or drninsLI H,navingxan `inercia-,ning ve... depth, from eirenmfeenee 1to centenIn ,testinonythet I elailn the foregoing as my invention l have mynignatnrein the presenee of two Witnesses.

Jenn mineures.

Witnesses:

H nnnY FnANGIS Qvnnon, nninnnn .Hlrnnnws Crmenes.

